Kitchen exhaust system

Abstract

A kitchen exhaust system has an outside air supply blower and a hood exhaust blower discharging outside. 80% of the air discharged by the exhaust blower is taken from the intake blower through cooktop level and overhead supply outlets in the hood, and 20% is taken from the room. The supply discharge outlets are arranged to provide a venturi action removing smoke and fumes from over the cooktop.

The invention claimed is: 
     
       1. A kitchen exhaust system comprising: a hood for disposition above a cooking top;   a first blower for taking air from outside a building and discharging it into said hood;   a second blower for taking air and fumes from inside said hood for discharge outside a building;   a lower plenum located below the hood and connected to said first blower for discharging outside air upward into the interior of said hood;   an exhaust outlet from said hood and connected to said second blower;   air outlet means in said hood coupled to said first blower including flow-directing means for discharging air from said first blower across the interior of said hood toward said exhaust outlet;   said air outlet means in said hood include registers horizontally spaced along an inner front wall of the hood near the bottom of the hood and having vanes inclined upward toward the rear of the hood to direct fresh air upwardly and rearwardly from the lower front to the upper rear of the interior of the hood;   said hood includes an upper plenum coupled to said first blower and receiving fresh air therefrom;   at least one fresh air conduit is connected to said upper plenum to receive fresh air from said fist blower and conduct it downwardly to said lower plenum; and   a second fresh air conduit horizontally spaced from said first conduit and generally parallel thereto and connected to said upper and lower plenums, said lower plenum being a horizontally extending tube having its opposite ends connected to said conduits; said conduits discharging fresh air into said opposite ends whereby air flow is toward the middle of said lower plenum.   
     
     
       2. The apparatus of claim 1 wherein: said lower plenum has a top opening throughout its length for upward discharge of air therefrom.   
     
     
       3. The apparatus of claim 2 and further comprising: a generally planar back plate extending between said conduits and upward and forward from the rear margin of said top opening forward to a line at front margins of said conduits at said hood, to continuously direct air discharged upwardly from said lower plenum in a slightly forward direction to cooperate with air directed upwardly and rearwardly from said register to create a venturi action to move room air from above a cooking top under the hood upward into the interior of said hood.   
     
     
       4. The apparatus of claim 3 wherein: a cooktop is located under said hood; and   the cooktop and the top opening of said lower plenum are at substantially the same level.   
     
     
       5. The apparatus of claim 3 and further comprising: a pair of air flow splitters in said lower plenum extending from the upper outer ends of said top opening downward and inward to the bottom center of the lower plenum and having a plurality of vanes therein, the vanes being configured such that air flowing from the lower ends of said conduits toward the center of said lower plenum is split and directed vertically upward throughout the length of said opening thereby producing a uniform upward flow of air across the length of said opening to minimize areas of reduced flow or lower pressure caused by increased air turbulence.   
     
     
       6. The apparatus of claim 3 and further comprising: filter means in the rear of said hood between the interior and the exhaust outlet for filtering air and fumes pulled by said second blower from the hood for discharge outside the building;   thermal insulating sheet material lining the inside face of outer top and front walls of said hood for preventing radiant cooling of the room air while allowing cooling of hot cooking fumes in said hood thereby reducing the possibility of grease fires and increasing the efficiency of said filter means for grease removal.   
     
     
       7. A kitchen exhaust air duct apparatus comprising: a first air conduit having an upper inlet for connection to an air supply from a blower;   a second conduit horizontally spaced from said first conduit and generally parallel thereto and having an upper inlet for connection to an air supply from a blower;   a horizontally extending tube having its opposite ends connected to lower outlet ends of said conduits whereby said conduits can discharge air into said opposite ends whereby air flow is toward the middle of said lower plenum;   and a hood having a fresh air plenum therein connected to said inlets for supplying air to said inlets from said blower;   said tube has a top opening throughout its length for upward discharge of air therefrom; and   a generally planar back plate extending between said conduits and upward and forward from the rear margin of said top opening forward to a line adjacent front margins of said conduits at said inlets, to continuously direct air discharged upwardly from said tube in a slightly forward direction.   
     
     
       8. A kitchen exhaust air duct apparatus comprising: a first air conduit having an upper inlet for connection to an air supply from a blower;   a second conduit horizontally spaced from said first conduit and generally parallel thereto and having an upper inlet for connection to an air supply from a blower;   a horizontally extending tube having its opposite ends connected to lower outlet ends of said conduits whereby said conduits can discharge air into said opposite ends whereby air flow is toward the middle of said lower plenum,   said tube having a top opening throughout its length for upward discharge of air therefrom; and   a pair of air flow splitters in said tube extending from the upper outer ends of said top opening downward and inward to the bottom center of the tube and having a plurality of vanes therein, the vanes being configured such that air flowing from the lower ends of said conduits toward the center of said tube is split and directed vertically upward throughout the length of said opening thereby producing a uniform upward flow of air across the length of said opening to minimize areas of reduced flow or lower pressure caused by increased air turbulence.   
     
     
       9. The apparatus of claim 8 and further comprising: a hood having a fresh air plenum therein connected to said inlets, and a fume collecting interior above and forward of said top opening.